Anxiety

Hi, I was just wondering if you could diagnose me as I think I've got something but I'm not sure what. It'll be something to do with anxiety I should think. A quick back story: For the first five years of secondary school I was bullied and as such I didn't have many friends, had a poor self-image, found it difficult to meet and talk to people and ultimately my social development was delayed by about 3 years. Then I got into 6th form and I met a guy who was funny, kind, loyal, genuine etc. who really brought me out of my shell and was the first person I could call a true friend. He gave me confidence, self-belief and the ability to laugh again. We become inseperable. I grew quite attached to him, clingy, you might say, as a result and when our friendship soured I endured a period of depression for three months until counselling helped me overcome it. Then I met this girl. She's fantastic, we immediately hit it off and got along so well - I won't go into details but the way she behaves it's like we've been best friends for years. Anyway, long story short, I'm afraid of losing her friendship and this preys on my mind all the time and I think this is what's wrong with me - I have a pathological need to always have someone close to me, I fear being alone and it affects me quite badly. What is this and is there some sort of way I can overcome the dependence on others for my own happiness?